Non Magnetic,  tarnish residue was black when I polished it, melts ice fast, I am not pro but it has the characteristics of silver. Stamped with D possibly? See pics. 

Cool style!

The product is a vintage silver plated collar choker torque necklace, made in the United States. It features a non-magnetic brass construction and does not bear any stamps or signatures. This original piece of vintage jewelry is stylish and timeless, perfect for adding a unique touch to any outfit.